The present invention relates to processes for the selective hydrogenation of vegetable oils in the presence of a catalytic agent containing micrometallic cobalt dispersed in a glyceride fat matric, and more particularly, the cobalt in the catalyst is separable from the hydrogenation product by the use on it of magnetic attraction and the hydrogenation products are edible products.
Numerous processes for selectively hydrogenating oils are already known. Use is very often made of the heterogeneous catalysis by reduced and activated metals, employed as they are or on a support, under particular conditions. From the most important of these catalysts, the systems based on copper, nickel, chromium may be cited. The principal disadvantageous found in such processes include losing their activity in the presence of poisons contained in the crude oils, such as certain non-glyceridic constituents; the considerable variation in quality of the catalysts depending on the conditions of manufacture; and after the hydrogenation is terminated, the protracted and difficult elimination of the catalyst, so that the catalyst cannot be immediately reused, or even regenerated in certain cases.
Attempts have been made to solve these problems by refining preceding the hydrogenation; varying the quality of the catalyst; separation of the catalyst from the hydrogenation products.
A process is also known for the preparation of a catalyst, as shown in Ellis, U.S. Pat. No. 1,390,683, who works only with nickel compounds. Such compounds are extremely toxic and thus have never been used for the selective hydrogenation of vegetable oils to obtain edible products: One percent of nickel in the human body causes cancer. These catalysts were fats, for hardening oils having low melting points to obtain facts, such as lubricants and other products not destined for human consumption. They were not utilized for selective hydrogenation to obtain edible products.
The showing of Ellis is also contrary to the present invention in the choice of catalyst support. Ellis, in effect, requires an inert product which does not produce a saponifiable product in the reaction environment. Glycerides are particularly excluded.
The Ellis catalyst is prepared above all for its storage prior to use. Moreover, it is proven pyrophoric. Once used, it is poisoned, and thus cannot be reused.